Security systems for remote sensing and control of activity in security areas apart from central locations require more functions, more data, and lower costs than previous systems. Their functions include monitoring of secure areas for unauthorized use and remote control of events within the secure areas. Particular events must be specifically reported in a manner most likely to provide a timely response from the operators of the security system. To command the attention of the operators, the reported data must be ordered, reliable, specific, and clear. However, to be an economically viable system, it must also be compact, operationally flexible, easy to use, and inexpensive.
In previous systems, the attempt to combine all the above-mentioned features in a single security system has been only partially successful, sacrificing one or more of the above-mentioned requirements. For instance, the specific needs of the system constantly change according to the change in usage and size of the secured area. In wired-logic systems, this flexibility requirement can only be accommodated by appropriate changes in hardware, which often are significant, protracted, and expensive.
The security system is frequently required to perform tasks in addition to reporting fire and break-in alarms. These additional tasks include detailed prioritized visual and audible alarms, as well as a clearly readable annunciation of the alarm condition. System sophistication at this level cannot be implemented without substantial information handling capacity, typically that of a computer system.
To meet the above-mentioned requirements, the security system naturally grows in complexity. At the same time, the reliability of the system must be maintained at a high level, if not improved over the earlier, simpler systems. However, since the increased performance is generally provided only by annexing greater amounts of hardware, the reliability problem worsens.